I think you should check with Vandersteen to learn if the "standard" crossover unit is available in a balanced configuration. As I recall, the "standard" crossover comes only with RCA jacks.
However, the Vandy Model 5 crossover (comes in 2 stainless steel enclosures -- one per channel) can be ordered with either balanced or unbalanced inputs. The Model 5 crossover is pricey when purchased new: the balanced configuration is $800, and the RCA configuration is $600. I can verify, however, that the Model 5 crossovers are virtually seamless, and allow for near-perfect (nothing's perfect, after all) integration with the main speakers.
However, the Vandy Model 5 crossover (comes in 2 stainless steel enclosures -- one per channel) can be ordered with either balanced or unbalanced inputs. The Model 5 crossover is pricey when purchased new: the balanced configuration is $800, and the RCA configuration is $600. I can verify, however, that the Model 5 crossovers are virtually seamless, and allow for near-perfect (nothing's perfect, after all) integration with the main speakers.